Preventing the defaults of unset object properties from being overridden in a JS function

Question

So, I have a function with an object as a parameter:

function example(options = { param1: true, param2: 42 })
{
   return options.param2;
}

The problem is, if I call the function with parameters like this:

example({ param1: false });

the default for options.param2 gets overridden and set to undefined, even though it wasn't defined when the function was called. I realize why this is (the object is all one parameter so the entire thing gets set when you call the function), but is there any easy way to prevent this from happening, short of making all of the object parameters their own arguments in the function?

score 0 · Accepted Answer · answered Mar 07 '22 at 05:24

0

Destructure the argument instead, and assign default destructured values.

function example({ param1 = true, param2 = 42 } = {}) {
   return param2;
}

answered Mar 07 '22 at 05:24

CertainPerformance

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perfect, also how would I JSDoc this? just use @param for each one? – frielmv Mar 07 '22 at 05:28
https://stackoverflow.com/a/25778441 looks to do what you want – CertainPerformance Mar 07 '22 at 05:29

Preventing the defaults of unset object properties from being overridden in a JS function

1 Answers1